Segregation of affluence not only concentrates income and wealth in a small number of communities, but also consecrates social capital and political power. As a result, any self-interested investment the rich make in their own communities has little chance of “spilling over” to benefit middle‐ and low-income families. In addition, it is increasingly unlikely that high‐income families interact with middle‐ and low‐income families, eroding some of the social empathy that might lead to support for broader public investment in social programs to help the poor and middle class.

The segregation finds its ways into public schools, too, as Little Rock knows well. The damage from the loss of exposure of poor kids to kids of different strata is incalculable.

Interesting stuff about political influence of the upper income strata and its liberal leaning, at least on social issues. This has implications for tension in both the Republican and Democratic parties.

Edsall notes that the well-off vote at higher percentages than lower income people.

Edsall's conclusion:

It turns out that the United States has a double-edged problem — the parallel isolation of the top and bottom fifths of its population. For the top, the separation from the middle and lower classes means less understanding and sympathy for the majority of the electorate, combined with the comfort of living in a cocoon.

For those at the bottom, especially the families who are concentrated in extremely high poverty neighborhoods, isolation means bad schools, high crime, high unemployment and high government dependency.

The trends at the top and the bottom are undermining cohesive politics, but more important they are undermining social interconnection as they fracture the United States more and more into a class and race hierarchy.